Abstract 12580: Impact of Zero Coronary Artery Calcium on Downstream Cardiac Testing
Bibliographic record
Abstract
Introduction: While coronary artery calcium scoring (CAC) has emerged as a useful tool for cardiovascular disease (CVD) risk prediction, its impact on downstream resource use remains unclear, especially in those with zero CAC. The purpose of this study was to determine the relationship between zero CAC and downstream use of cardiac procedures. Methods: Consecutive CAC scores from two academic hospitals in Toronto, Canada, from 2011 - 2019, were linked to population-based databases. Subjects with zero calcium without previous CVD were subsequently propensity score-matched with a non-CAC-tested control group for age, sex, CVD risk factors and comorbidities relevant to receipt of testing. Downstream cardiac testing, myocardial infarction (MI), stroke, and congestive heart failure (CHF) hospitalizations were compared between the two groups. Results were analyzed using descriptive statistics and Cox proportional hazards regression models. Results: 4,884 patients (Mean 56.8y, SD 11.3) underwent CAC scoring, of whom 2,709 (55.5%) had zero CAC (Mean 52.9y, SD 10.6, 55.4% women). Compared to those not tested at 90 days, zero CAC subjects had similar graded exercise stress test (GXT) (72 tests vs 60, p = 0.29), stress echocardiography (40 vs 32, p = 0.34) and myocardial perfusion imaging (MPS) (26 vs 37, p = 0.15), but higher cardiac MRI (CMR) (48 vs 7, p < 0.001) use. At 3.4 years, GXT (HR 1.24, 95% CI 1.14 - 1.35), stress echocardiography (HR 1.80, 95% CI 1.59 - 2.05) and CMR (HR 3.40, 95% CI 2.55 - 4.53) use was higher in the zero CAC group, whereas MPS (HR 1.08, 95% CI 0.97 - 1.21) and catheterization (HR 1.14, 95% CI 0.91 - 1.44) were similar and PCI (HR 0.59, 95% CI 0.35 - 0.98) and CABG (HR 0.14, 95% CI 0.03 - 0.61) were lower. There was an approximately 5-fold lower rate of MI (HR 0.22, 95% CI 0.10 - 0.51) in the zero CAC group at 3.4 years and no difference in stroke (HR 0.98, 95% CI 0.46 - 2.05) or CHF hospitalizations (HR 1.15, 95% CI 0.53 - 2.48). Conclusion: Zero CAC was associated with higher use of some non-invasive cardiac testing, similar use of catheterization, and reduced PCI, CABG and AMI when compared to a propensity score-matched control group. The results support the utility of a zero CAC in limiting invasive procedures while maintaining an association with reduced cardiac events.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.008 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".